JPH01186333A - Wire type dot printing head - Google Patents

Abstract

PURPOSE:To obtain a high speed printer enhanced in the heat transfer and radiation effect of a yoke member and imparting high printing quality by allowing the inner peripheral wall of a metallic yoke member to be adjacent to an exciting coil corresponding to the outer shape thereof as close as possible within a range not becoming insulation inferiority. CONSTITUTION:A yoke member 3 is composed of a magnetic material having a bottomed cylindrical shape and integrally formed along with the coil core 3a arranged to the inner surface thereof in a ring form and constituted of the outer peripheral parts 3b-3e of the yoke member 3 adjacent to the outer peripheral contour of the exciting coil 4, which is wound around the coil bobbin 18 mounted to the coil core 3a, as close as possible. When a current is applied to one or plural exciting coils 4 selected by a printing order signal, the magnetic flux flowing through the bottomed cylindrical yoke 5 and a side yoke 6 from the coil core 3a through the yoke member 3 is opposed to the coil core 3a to flow in the armatures 8 having a ferromagnetic property provided on both sides of a drive lever 7 and the drive lever 7 is attracted to the coil core 3a to revolve in a clockwise direction. The printing wire 10 held to the leading end of the drive lever is allowed to impinge against recording paper 20 through an ink ribbon 19 to perform printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a yoke member that constitutes a magnetic path in a wire-type dot printer. □ [Prior Art] As shown in FIGS. 7 and 8, the yoke member 73 of the conventional wire-type dot printer head is part of the magnetic circuit that drives the wire, and also transfers the heat generated by the excitation coil to the outside. The yoke member 73 conducts and radiates heat to
There is a problem that the gap between the coil and the outer circumferential surface of the excitation coil is large (which may deteriorate the heat dissipation effect).

(Problems to be Solved by the Invention) The present invention has been made in view of the above problems, and its purpose is to improve the heat transfer and heat dissipation effects of the yoke member, and to provide a printer that achieves high speed and high printing quality. The goal is to provide the following.

[Means to solve the problem]

That is, the present invention is characterized in that the yoke member is arranged very close to the outer peripheral contour of the excitation coil, which is a heat generation source.

〔Example〕

The details of the present invention will be explained below based on illustrated embodiments.

FIG. 1.2 shows an embodiment of the wire dot printer according to the present invention, in which reference numeral 2 denotes a nose 2a holding a wire guide 11.12 and a spring 16 to be described later.
This is a guide holder in which a guide portion 2d for attaching the wire 10 and a guide portion 2f for the wire 10, which will be described later, are integrally formed.
A shallow cylindrical yoke member 3, which will be described later, is integrally fixed thereto, and is made of a magnetic material and has a plurality of coil cores 3a, which will be described later, formed in a ring shape. A bottomed cylindrical yoke 5 and a disc-shaped wide yoke 6 made of magnetic material are placed thereon, and a shaft 9 that penetrates and holds a wire drive lever 7, which will be described later and engages with a wire 10, is mounted on the yoke 5. It is placed on the yoke 5 and supported by the shaft supporting lateral groove 6a provided in the side yoke 6, and a presser plate 14 is placed on top of it so as to cover these. The fastening plate 1 is suspended between the plate 14 and the nose cover 1.
They are integrally connected by 5. In addition, the number 18 in the figure
1 is a coil bobbin attached to the coil core 3a, around which an excitation coil 4 (to be described later) is wound; reference numeral 17 indicates a terminal portion of the excitation coil 4 and the bottomed cylindrical yoke member 3;
The printed circuit boards are respectively shown attached through the wires. Further, the drive lever 7 is always urged to the non-printing position by the spring 16 interposed between the drive lever 7 and the cylindrical portion 2d of the guide holder 2.

In the printer configured in this way, one or more exciting coils 4 selected by the print command signal
When a current is applied to the coil core 3a, the magnetic flux flowing through the yoke member 3, the bottomed cylindrical yoke 5, and the side yoke 6 opposes the coil core 3a, and the ferromagnetic flux provided on both sides of the drive lever 7 The drive lever 7 is attracted to the coil core 3a, rotates clockwise in the figure, and strikes the print wire 10 held at the tip onto the recording paper 20 via the ink ribbon 19. Perform printing.

Figure 3.4 shows the above-mentioned yoke member 3, which is a characteristic part of the present invention.
The yoke member 3 is made of a magnetic material and has a cylindrical shape with a bottom, and is integrally formed with the coil core 3a arranged in a ring shape on the inner surface.
The yoke member 3 is located as close as possible to the outer peripheral contour of the excitation coil 4 wound around the coil bobbin 18 attached to a.
It is composed of outer circumferential parts 3b, 3c, 3d, 3e, etc.

-3= In the figure, reference numeral 22 is interposed between the excitation coil 4 and the yoke member 3, and the heat generated from the excitation coil 4 is transferred to the yoke member 3.
It is a filler such as silicone resin that has high thermal conductivity to conduct the heat to.

Therefore, the operation of the yoke member 3 configured in this way will be explained.
When a current is applied to one or more excitation coils 4,
This input electric energy is applied to the exciting coil 4, the coil core 3a, the yoke member 3, and the bottomed cylindrical yoke 5.
, the side yoke 6, the armatures 8 provided on both sides of the drive lever 7, etc. are converted into magnetic energy in a magnetic circuit, and the drive lever 7 is attracted to the coil core 3a, and the tip wire 10 of the bar 7 is used for driving. Printing is performed by , that is, it is converted into mechanical energy.

However, in general, the electrical and mechanical energy conversion efficiency is only a few percent, and most of the input electrical energy is
The heat is lost within the excitation coil 4 as heat. The adverse effect of heat generation is that the input electrical energy is suppressed due to an increase in the coil resistance of the excitation coil 4, which reduces the mechanical energy, which in turn leads to deterioration of printing quality. This increases heat generation, which hinders high speed and high print quality.

Although a filler 22 having relatively high conductivity as a non-metal is interposed between the yoke member 3 and the excitation coil 4, its thermal conductivity is significantly lower than that of the yoke member 3.

Therefore, the heat transfer and heat dissipation effects between 3b, 3c, 3d, and 3c of the metallic yoke member 3 configured as in the present invention are enhanced,
In turn, it becomes possible to enhance the heat dissipation effect to the outside air, thereby achieving higher printer speeds and higher printing quality.

FIG. 5 shows a second embodiment, in which the yoke member 3
The parts 3a, 3e, 3a, etc. that make up the parts are separate parts.

FIG. 6 shows a third embodiment, in which the excitation coil 4
The entire outer circumference of the yoke member 3 is covered with the yoke member 3 to improve heat conduction and
[Effects of the Invention] As explained above, according to the present invention, the inner circumferential wall of the metallic yoke member can be made to correspond to the external shape of the excitation coil as much as possible without causing poor insulation. By placing them as close to each other as possible, the heat transfer and heat dissipation effects in the yoke member are enhanced, and by suppressing the temperature rise of the excitation coil, the resistance value of the excitation coil is prevented from increasing, and in other words, the electrical energy input to the excitation coil is reduced. This prevents the reduction in printing energy, prevents deterioration of printing quality, and enables higher speeds.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a device showing an embodiment of the present invention, Fig. 2 is a plan view of the main parts of the same device, Fig. 3 is a detailed view of the main parts of the invention, and Fig. 4 is the same as Fig. 3. 5 is a sectional view showing the second embodiment, FIG. 6 is a plan view showing the third embodiment, FIG. 7 is a plan view showing the conventional example, and FIG. FIG. 1...Nose cover 2...Guide holder 2a...Nose portion 3...Yoke member 3a...Coil cores 3b, 3c, 3d, 3e...Yoke member outer circumference 4...Exciting coil 5... - Bottomed cylindrical yoke 6... Side yoke 7... Drive lever 8... Armature 9... Fulcrum shaft 10... Wire 11.12... Wire guide 13... Damper 14... - Pressing plate 15... Fastening plate 16... Return spring 17... Circuit board 18... Coil bobbin 19... Ribbon 20... Printing paper 21... Platen and above Fig. 3

Claims (1)

[Claims] A wire-type dot printer head, characterized in that the excitation coil is attached to a groove of a yoke member in which a groove having an inner circumferential wall having a shape corresponding to the external shape of the plurality of excitation coils is formed.